jacking up joist

Graven Water · 2011-06-03T01:33:46+00:00

A joist below my bathtub was severeley cut for the bathtub drain plumbing. Picture at can see where it rests on the sill plate at the right. There's only about 2" of joist left at the sill plate. The bathtub is out. The vertical stub went up to the bathtub overflow. The bathtub sits perpendicular to the joists, so the drain is between joists. The cut would have been done 50 years ago. I'm thinking of strengthening it, partly because I'm planning to put a stone or tile floor in my bathroom and I don't want it to crack if someone fills the bathtub and the floor sags. I'm not sure whether strengthening the joist is necessary. Rather understandably, the joist is sagging. The LH side sags about 1/4" below horizontal, and the joist sheared slightly at the edge of the sill plate. It seems like the best way of strengthening it would be to attach 2" steel angle - L-beams - on both sides of the joist, with the legs of the L'ssticking out horizontally. I'm thinking of jacking up the sagging part so it's straight before attaching the steel angle, though. How would this be done? The joist is over my garage. Could I raise it a little by hammering in a 2x4 under it that's a little longer than the distance between the joist and the garage floor?-Laura

jacking up joist FAQ

Jun 03, 2011 40 Replies

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So, I'm planning to attach a steel plate to the front side of this joist, and a 2x10 to the back side. The plumber said he can make a single hole through a steel plate for the drain pipe, it would not be a big cutout.

Picture at

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What thickness should the steel plate be? It can rest on the sill plate, and extend about 15" past the cut part of the joist. Farther if it's notched to make room for a 2x4 attached to the joist.

I got a big floor jack and I'm raising the joist to horizontal very slowly. 16" out from the sill plate, it sags about 1/3" below horizontal. That's a lot of bend in a short distance, so I figured I'll take about a month to jack it up.

thanks Laura